2004 v70 limp mode/brake problem

Faust · Post by **Faust** » 25 Feb 2015, 11:57

"fully charged" well I doubt it. By the time I got it home the lights were a little dim. It did start on its own and I let it run about 1/2 an hour. Unfortunately, my battery charger is in my workshop on the other side of town and I can't get to it.

Sardine · Post by **Sardine** » 25 Feb 2015, 12:25

My 2004 V70 acted funny when I let my battery run down. I could still started it, but it wouldn't run. With the battery fully recharged, it still did not help. A brand new battery and still the same. Finally a CPU reset did it. The car still runs beautifully 3 years later. Your symptoms are different from mine, but I guess a crazy CPU can do anything.

Faust · Post by **Faust** » 26 Feb 2015, 10:40

Background. Last Sunday I snapped my serpentine belt. I drove it home but battery was almost dead. Tuesday I replaced the belt. The only thing out of the ordinary is that I removed the ECM cover to get clearance. After, the car started right up and ran normally until I touched the brake pedal to move from Park. It fell to idle and would not respond to the accelerator pedal. I have tried to reset the ECM by disconnecting battery, etc. Seems to be no diference. I will try it again.

I called local Volvo Indie. He sugggested reset computer, if no help go to dealer.

Does the 2004 v70 have some kind of brake-throttle override?

Post by **vtl** » 26 Feb 2015, 11:04

Is there a chance you touched TCM (transmission control module) which sits next to ECM?

Faust · Post by **Faust** » 26 Feb 2015, 11:08

vtl wrote:Is there a chance you touched TCM (transmission control module) which sits next to ECM?

It's possible. It's snowing again, when it stops I will check if it is loose.

Faust · Post by **Faust** » 26 Feb 2015, 12:36

Just called dealer. This is not a standard problem, all they can suggest is that i tow it in for an exploratory.

Post by **abscate** » 27 Feb 2015, 11:14

Mod note - merged threads on brake and electronic drive problem..

Faust · Post by **Faust** » 27 Feb 2015, 14:38

SOLUTION - Not being willing to pay the dealer to explore, I took it to the best eqipped Indie I knew. Scanning gave a Code of 950c, that did not show up in his data files. Scanning through the data files we found a reference to fuses, not listed as causitive. Fuses 7 & 8 in the underhood box. We had also noticed that the cooling fan for the ECM box was not operating. We finally decided to have a look at the fuses mentined and found one blown. It was fuse number 8. I am not looking at the box but I recall that it lists the ECM fan. We replaced #8 and everything is fine. The fan is directly under the power steering fluid reservoir. The only way I connect this to changing the serpentine belt is that I removed the reservoir for clearance. The fan wire is directly below it. It must be that somehow I shorted the fan wire, blowing the fuse. I cannot say what it is in the accellerator/brake circuits that is protected by this fuse. We really found it by happenstance. In truth, scanning threw codes for the Accellerator sensor and the ECM cooling fan not operating, but did not link them. Thanks to all responders.

bigbrain · Post by **bigbrain** » 27 Feb 2015, 16:06

Hey Faust....ahhh good point. On mine I have the DSTC and brake control module on the other side (your drivers side)....so is the BCM and DSTC stuff still on the drivers side or is that in the same place as mine. I'll be in LA next week....not looking forward to the driving too much. Wow 1770 is pretty old even for London....as I'm sure you know we really like our old stuff too

. My house is 1930....in London we call those the "new builds"

Faust · Post by **Faust** » 27 Feb 2015, 17:54

I won't go into detail on the solution to my problem (too long) in any case it turned out to be fuse #8 in the underhood fuse box. It is labeled ECM cooling fan. I had noticed the fan wasn't operating. No idea what brake or accellerator circuits are on that fuse. My assumption is that in changing the belt I removed the power steering reservoir to gain clearance. That reservoir sits directly over the cooling fan. In replacing it, I must have some how shorted the power wire to the fan, blowing the fuse. I had codes pulled and got 950c, accelerator pedal sensor. Didn't make sense but reading through the All Data files I found an offhand reference to fuses 7 & 8. #8 was the villian.

Bigbrain, There are a few older houses here abouts. My family has a 1737 house in North Carolina. That one was partially burned by Gen. Sherman in our "War of Northern Aggression" so it is not entirely original.